Mellemørebetændelse

Resumé

Infectious middle ear disease
By Niels Lynnerup, Morten Qvist and Preben Homøe

Evaluation of general health is important in order to reconstruct the life conditions of earlier populations. This is usually done by analysing the skeletal remains of such populations. However, only few diseases leave their mark on the skeletons – indeed the most widespread and common diseases, such as pneumonia and gastrointestinal infections, which probably also accounted for the vast majority of deaths, do not leave any signs at all on the skeleton. Chronic conditions, on the other hand, such as tuberculosis and leprosy, do leave their mark, but the picture one gains by focusing on these diseases says more about the hardiness of a population (namely that individuals endured a lifelong disease) than about the general health. Palaeopathologists have sought for such markers, e.g. osteoporosis, Harris’ lines, dental enamel hypoplasia and porotic hyperostosis, but many of these methods either suffer from biased scoring methods, or the link to modern medical clinical observations is tenuous. We present a new method to evaluate general living conditions in earlier populations. Our method relates to the occurrence of chronic middle ear disease in childhood, and we think it has several advantages: correspondence between chronic infectious middle ear disease (IMED) and general living conditions is affirmed in modern medical epidemiological observations, the bone changes brought about by IMED occur in childhood, and the skeletal element used to evaluate the occurrence of IMED is the petrous part of the temporal bone in the skull, one of the sturdiest bones in the skeleton. We applied this method to three medieval skeletal materials from Nordby, an early medieval rural parish churchyard (function period approximately AD 1050-1250), Tirup, also a country parish churchyard, but from the later medieval period (function period approximately AD 1150-1350), and finally a monastic churchyard, used as parish churchyard for the citizens of Aalborg, one of the larger cities of medieval Denmark (function period approximately AD 1240-1530). The intact skulls from these churchyards were X-rayed from each side, and the area of the so-called pneumatic cells in the occipital bone was measured. From earlier studies we have proved the relationship between cell size as seen on X-ray photographs and occurrence of IMED earlier in life. Also, this relationship has been expressed mathematically, so that the left and right side cell area size may denote the risk of the individual having had or not having had IMED in childhood. The results showed that there was a pronounced rise in the frequency of IMED from the early to later medieval period. This seems to reflect the well-known agrarian crisis between the early and later medieval period: probably mainly due to land overuse and climatic changes, the population levels fell, and, as observed at Tirup, childhood mortality rose. Also, at this point in time, plague hit Denmark, further stressing population health. Our results also showed that the highest frequency was found in Aalborg, which may be explained by increased pathogen load in a more densely populated urban centre.